1. Field of the Invention
The present invention relates generally to an input apparatus capable of a touch and a pen input, and more particularly, to a method and apparatus for detecting and correcting an input error in the input apparatus.
2. Description of the Related Art
Many display devices employ a touch screen input scheme in which a user may input data by directly touching the screen using his or her fingertip or a stylus pen. This touch screen input scheme is mainly adopted in personal mobile terminals such as, for example, a smart phone, a mobile phone, a notebook computer, an All-in-One Personal Computer (PC), a tablet PC, and a Portable Multimedia Player (PMP). An intuitive and convenient user interface may be provided via the touch screen input scheme, which specifically allows for the inputting information about a position that a user has indicated by touching a specific position on a display screen instead of using a keyboard, a mouse, and physical buttons. A pen-based touch input scheme is suitable for graphic works such as, for example, Computer-Aided Design (CAD).
The touch screen input scheme, which is also referred to as digitizer and an Electric Graphic Input Panel (EGIP), may be roughly classified into a resistive scheme, a capacitive scheme, and an ElectroMagnetic Resonance (EMR) scheme, according to the method of detecting the position indicated by the user.
The resistive scheme detects a position pressed according to pressure by detecting a change in current with a Direct Current (DC) voltage applied thereto. Specifically, the resistive scheme may detect a direct contact between two thin conductive layers on the screen due to pressure from a fingertip or a stylus pen. The resistive scheme may detect any object, regardless of whether it is a conductor or a non-conductor, because this scheme detects position by pressure.
The capacitive scheme detects a touch point using capacitance coupling with an Alternating Current (AC) voltage applied thereto. Specifically, the capacitive scheme may detect only the conductive object, and requires a contact area greater than or equal to a predetermined area to ensure a detectable change in capacitance. Therefore, the capacitive scheme may detect a position when the user inputs data using his or her fingertip. However, when the user inputs data using a conductive tip, the capacitive scheme may not detect the position due to the small contact area caused by the conductive tip.
The EMR scheme employs a digitizer sensor substrate including an array of loop coils. Accordingly, if the user moves a pen, the pen is driven by an AC signal to cause an oscillating magnetic field, which induces a signal in the coils. The position of the pen is detected based on the signal induced in the coils.
Unlike the resistive scheme, the EMR scheme does not necessarily have the sensor substrate disposed in front of a display module. Instead the EMR scheme may have the sensor substrate disposed at the rear of the display module, because this scheme disposes a plurality of coils on the substrate and identifies a position of the pen by detecting a change in electromagnetic field occurring by an access of the pen to the sensor substrate.
Accordingly, a multi-input apparatus capable of both a digitizer (touch) input of the EMR scheme and a touch input of the capacitive scheme may be provided. However, when a part of the hand touches the touch screen during pen input, an input unintended by the user may occur.